Traffic observing and recording apparatus



Oct. 11, 1938. A. 'r. SIGO 2,132,808,

TRAFFIC OBSERVING AND RECORDING APPARATUS Filed Jan. 2, 1934 4 Sheets-Sheet l FIG.I

' |NVENTOR ARTHUR T.' 5160 Oct. 11, 1938. A. T. SIGO 2,132,808

TRAFFIC OBSERVING AND RECORDING APPARATUS Filed Jan. 2, 1934 4 Sheets-Sheet 2 FIG. 4

INVENTOR ARTHUR T. 5160 ATTY.

Oct. 11, 1938. A. 'r. SIGO TRAFFIC OBSERVING AND RECORDING APPARATUS Filed Jan. 2, 1934 4 Sheets-Sheet 3 ATTY.

Oct. 11, 1938.

A. T. sr o TRAFFIC OBSERVING AND RECORDING APPARATUS Filed Jan. 2, 1934 4 Sheets-Sheet 4 New 3x Osmium own-En omm m omm an 0.

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|NVENTOR ARTHUR T. W

SIGO W/ ATTY.

Patented Oct. 11, 1938 UNITED STATES PATENT OFFICE TRAFFIC OBSERVING AND RECORDING APPARATUS ware Application January 2, 1934, Serial No. 704,851

37 Claims.

The present invention relates in general to traflic observing and recording apparatus; for example, such as is used in telephone systems for obtaining and recording traffic information.

5 It is one of the functions of the trafiic department of an operating telephone company to make trailic studies for determining such things as the number of 10st calls, the efiiciency of trunk groups, the necessity of providing additional 10 trunking facilities, etc. In order to make these studies, various kinds of information must be obtained by actual observation on the groups of trunks. It is the object of the invention, more specifically stated, to provide apparatus for ob- [5 taining such information accurately and economically, and for recording the same so that it can be used when required.

Although the apparatus disclosed herein has been designed with special reference to telephone to systems, it has been found to be useful in many other situations. In factories and industrial plants the apparatus can be used to record the operations of machines as to which data is required for making efliciency studies, or to record :5 any events as to which information in permanent form is required. Railroads also may use apparatus of this kind to record the movement of trains or the operation of switches in yards or at crossings. Various other applications are contemplated, and it will be understood, therefore, that although the operation of the apparatus will be described as it is used in a telephone system the invention is not limited to such use.

In view of the nature of the apparatus and the use which is made of it, it has been found advantageous to adopt a form of construction which involves a number of separate units of equipment, each of which has its particular function to perform in obtaining and recording informa- 0 tion. Several of these units may be used independently in obtaining certain information, while each of them may be used in connection with one or more of the others in obtaining information of a more complicated character. These units 5 will be referred to hereinafter as a multiple pen recorder, a circuit function counter, a line relay set, and a meter set.

The complete system including the several apparatus units and the operation thereof, will be 0 described hereinafter with reference to theaccompanying drawings, in which;

Fig. 1 is a front view of the multiple pen recorder;

, Fig. 2 is a section on the line A, Fig. 1, except 5 for thebase;

Fig. 3 is a section on the line B, Fig. 1, also excepting the base;

Fig. 4 is a detailed view of one of the pens;

Fig. 5 is a detailed view, partly in section, on line C, Fig. 3, of a. portion of the pen assembly; 5 Fig. 6 is a view of a portion of the recorder shown in Fig. 1 as it appears from the right, a

partial end view, in other words;

Fig. '7 is a circuit diagram of the multiple pen recorder; 1

Fig. 8 is a circuit diagram of a line relay set;

Fig. 9 is a record of a typical telephone call;

Fig. 10 is a circuit diagram of the circuit function counter;

Fig. 11 is a circuit diagram of a meter set;

Fig. 12 is a. view, partly in section, which shows the construction of one of the meters; and

Fig. 13 is a portion of a chart used for entering and compiling traffic information.

The construction of the multiple pen recorder will now be described, reference being made to the drawings, Figs. 1 to 6, inclusive.

The apparatus is mounted on a hollow base 9| which is shown clearly in Figs. 1, 2 and 3. The base 9| may be made of sheet metal. Inside the base there is mounted a strip of ten pairs of keys, which may be of any well known type. The keys are in two rows. The buttons for actuating the first row of keys are indicated in Fig. l by the reference numerals Kl-KIO. The push so buttons for actuating the second row of keys are similarly indicated by reference numerals Kl l- K20. It may be stated that the key strip is supported inside the base by four screws 49, with the rows of buttons extending through openings in the edge of the base which are provided for this purpose, all as is shown clearly in the drawings.

The main frame of the pen recorder includes two end plates 92 and 93, Figs. 1, 2, and 3. These end members are bent over at the bottom as shown in Fig. 1 so as to form two feet resting on the base 9|, and secured thereto by heavy machine screws as shown in Figs. 1 and 2. In order to stiffen the frame, a heavy cross-rod 96 is provided. This cross rod has a portion at each end which is reduced in size and which is threaded. These reduced end portions pass through holes in the end plates 92 and 93, which are held firmly against the shoulders on the rod 96 by means of nuts screwed on the threaded ends of the rod. There is also provided a similar rod 94, which is rigidly secured between the two end members in the same manner as rod 96. The rod 94 supports one edge of a flat metal strip 58 or apron 95. This member 95 has one edge wrapped around the rod 94 and the other edge rests on the base 9I. It extends clear across from the member 92 to the member 93, as shown in Fig. 1, and provides a support for the roll of paper 99. 1

The mechanism for handling the record paper comprises an idler spool 84, a driven roller 91, two take-up spools and 86, and a take-up roller I3, shown in Figs. 1 and 3. The driven roller 91 is supported on a shaft 98 which is mounted in hearings in the two end plates 92 and 93. The take-up roller I3 is supported on a shaft I4. The two ends of the shaft I4 lie in slots I5 and I6,'which are cut in the end plates 92 and 93, respectively. The take-up spool 86, which can be seen clearly in Fig. 1, is supported on a shaft 86, forming part of the spool. Bearings for the shaft'are provided in the end plates 92 and 93. The shank of the spool is provided with knurled. portions such as I8. The spool 85 is constructed the same as spool 86.. The spool 84 is also constructed similar to spool 86, except that the shank thereof may be somewhat smaller in diameter and is not provided with the knurled portions such as I8. The paper supply roll 99 rests on the plate 95, and against the spool 84, as shown clearly in Fig. 3. The paper is brought around under spool 84, from which point it is carried upward and around over the driven roller 91. As shown clearly in Fig. 1, the paper is preferably perforated along each edge, and these perforations are engaged by pins on the two ends'of the roller in order to provide for a positive drive. From the roller 91 the paper is brought down to the take-up roller I3. The roller I-3, with the accumulated paper thereon rests on the two takeup spools 85 and 86. These take-up spools are positively driven by gears, as will be explained hereinafter, and the knurled portions thereon provide for rotating the take-up roller I3. As the paper accumulates on the take-up roller, the shaft I 4 of the latter rises up in the slots I5 and I6.

As shown in Fig. 1, two curved clips 36 and 31 are provided, which hold the paper in position on the driven roller 1. These clips are desirable because the take-up roller I3 will have to be lifted from position from time to time to remove sections of the paper record or is dispensed with altogether, and at these times the clips 36 and 31 keep the paper in position on the driven roll, with the pins at the ends thereof registering with the perforations in the paper. The clips 36 and 31 are mounted on a shaft 38, which is provided with bearings in the end plates 92 and 93. As shown in Fig. 6, the right-hand end of the shaft 38.is provided with a lever 39. Between the end of this lever 39 and a pin secured to the end plate 93 there is provided a coil spring 88 under tension, which tends to rotate the shaft 38 and hold the clips 36 and 31 in contact with the paper.

The power for driving the apparatus is furnished by a motor 26, shown in Fig. 1. The drawings show a bracket or support 25, on which is mounted a gear case 21. The motor 26 is mounted against the face of the gear case by means of two studs, such as 29. The shaft 28 of the motor extends into the gear case 21, as shown. By means of suitable reduction gears which are enclosed in the gear case, the motor transmits power to' the shaft 30 which projects from the right-hand'side of the gear case. The

7 -motor 26 may be of any suitable design, except off the roller 91. speed which is somewhat higher than that which that it should be of the synchronous type so that it will run at a constant rate of speed. The gear case 21 is also of well known construction and need not, therefore, be described in detail.

On the shaft 30 there is mounted a pinion 23, which may be held on the shaft by means of a set screw. The pinionis in mesh with the gear wheel 22, see Fig. 2, which is mounted on the shaft 98. Thus, the pinion 23 and gear wheel 22 provide for driving the roller 91. There is provided an idler gear 2| whichis mounted on a stud secured to the end plate 92. Gear 2I is in mesh with gear 22 and is driven thereby. The spool 85 is provided with the, pinion 20, secured thereto as shown in Fig. .2, which is in mesh with the gear 2 I A small idler gear I1, mounted on a stud which is secured to the end member 92. serves to enable the pinion or gear 20 to drive the pinion I9 which is attached to the takeup spool 86. It will be seen that the spools 85 and B6 are driven in the proper direction so that they both tend to rotate the roller I3 in the proper direction to wind up the paper as it comes These spools are driven at a is required to rotate the roller I3 fast enough to keep the paper taut.

The shaft 30 which transmits power from the gear box 21 also has mounted thereon a circular cam 3|, shown in Figs. 1 and 2. This cam may be mounted on a hub which is provided with a set screw so that it can be secured to the shaft 38 like the pinion 23; On the gear box there is mounted a bracket 32, to which are secured by the usual screws and washers a pair of contact springs 33 and 34. As shown in Fig. 2, the outer contact spring 33 has a bent-over end portion which engages the periphery of the cam 3I. As the cam rotates the end of spring 33 will enter the successive notches which are cut in the edge of the cam, and spring 33 thus closes contact with spring 34. The gear ratio may be such that the shaft 30 makes one revolution per minute. Since there are ten notches cut in the periphery of the cam, the spring 33 will make contact with spring 34 ten times per minute. A source of potential may be connected to one spring, as will be explained subsequently, and an impulse lead may be connected to the other spring. With this arrangement impulses will be delivered to the impulse lead at the rate of ten impulses per minute.

It will be seen that the motor and gear box together with the cam and pinion carried by the shaft 30, form a detachable unit which. is supported by the bracket 23 in the proper position so that the pinion 23 will engage the gear 22. However, this unit may be removed if desired, by merely taking out the screws by which the gear case is attached to the bracket 25. This permits the motor and gear unit to be used separately if desired in case a source of timed impulses is wanted for some purpose which does not require the use of the pen recorder, assuming, of course, that the latter is not in use at the time. The motor is preferably provided with a flexible cord, as shown in Fig. 1, which terminates in a plug so that the motor can be connected up to a source of power.

As shown in Fig. 1 there are-twelve pen relays. These twelve relays control twelve recording pens, which are numbered from left to right as pens 1 to 12, inclusive. The pen relays are mounted in a ro\7v on a drilled cross member 43 and which are formed integrally with it and which extend forward at right angles to it.

arm 44 is pivoted in end plate 93 of the frame a at 46. A stop 48, Fig. 3, limits the rotation on the pivots in one direction. The arm 44, Fig. 6, has an adjustable stop screw. 41 which limits the rotation in the other direction. There is a similar stop screw carried by arm 43. It may be stated that this limited movement of the cross member 42 is provided so that the recording pens can be lifted from the paper. The

the pens will rest properly on the paper.

The pen relays are constructed along conventional lines. Each relay comprises a heel piece 50 and a coil II, as shown in connection with the relay which can be seen in Fig. 3. A machine screw passes through the drilled cross bar 42, through the heel piece and into the threaded end of the relay core. In this manner the pen relays are securely supported on the cross bar. Each pen relay has three springs such as 52, 53, and 54, which are attached to the heel piece by means of machine screws as shown in Fig. 3. The springs are suitable insulated from each other. The two upper springs are contact springs and are normally separated from each other. The lower spring 54, which is operated by the armature 55 of the relay, provides .for operating the associated recording pen, and also by means of a bushing operates the spring 53. The recording pens are supported on a cross bar 6|, which can be seen in Figs. 1, 3 and 5, the latter being a part sectional view which shows the left-hand end of the bar I. The bar 6| is supported on two brackets such as 63..

The left bracket 53 is secured to the heel piece of the first pen relay H as shown in Fig. 3. There is a similar bracket at the other end of the bar 8| which is similarly attached to the heel piece of the last pen relay 82. Each recording pen comprises a member 58, a spring member 59 which is riveted thereto, and the pen proper, indicated by the reference numeral 60. The detailed construction is shown, in Fig. 4. The pen proper comprises a small cylindrical ink well 60, open at the top, and having a hollow stylographic pen point projecting from the lower side thereof through an opening in the spring member 59. The pen 68 is held in two pairs of clips formed at the end of the spring member 59. The manner in which the. record- 'ing pens are supported on the cross bar 6| is shown clearly in Figs. 4 and 5. The cross bar Si is provided with twelve short studs or pivot pins 65, which fit loosely in holes drilled in the members 58 of the respective recording pens.

There is also a bar 64 which is secured to the the members 58 of the recording pens. Thus the recording pens are securely supported on a the bar 8| in such a manner as to provide for movement around the pivots 65. s

The recording pens are moved on their pivots by the associated pen relays. Each member 58 has a diagonal slot cut in the end thereof, and

,in this slot there is positioned a round pin 51,

which is securely attached to the operating spring 54 of the associated pen relay. Considering the first pen relay Ii, shown in Fig. 3, it will be seen that when the armature 55 is attracted the end of spring 54 carrying the pin 51 will be moved upward. This pin engages the side of the slots in member 58 of the recording pen and therefore moves the upper end of member 58 to the right, as seen in Figs. 1 and 4. The member 58 is therefore rotated slightly on the pivot 65, and the pen 6!] is moved to the left. When the relay deenergizes, the spring 54 resumes its normal position and accordingly moves the pen 60 back to its normal position.

The stop screw 41 should be adjusted so that the pen points press lightly on the paper. It will stop screws 41 are, of course, adjusted so that the line drawn by a recording pen when its associated relay is operated may be offset oneeighth of an inch from the position of the line when the relay is normal. It is preferable to use a special kind of ink which does not readily evaporate, manufactured for use in apparatus of this kind.

The reference numeral 80 indicates a terminal block, which may be mounted on the base 9!, as shown in Fig. 1. This terminal block is of the usual type such as is used in telephone systems on distributing frames. It comprises ten rows of terminals which are set in hard rubber or fiber blocks as seen clearly in Fig. l, which shows an end view of the block. There are pref erably ten terminals in each row. The terminals in the upper row are numbered from 1 ill to H0, the terminals in the second row from ill to I20, and so on. It will be understood that in actual practice the terminals may be numbered from 1 to 100, but in order to avoid confusion in the drawings the terminals are numbered herein as stated.

Fig. '7 shows how the pen relays and keys are wired to the terminal block. The conductors from the pen relays, the relay contacts, and the springs of the keys are preferably formed into cables which extend to the left-hand side of the terminal block shown at Fig. l, or to the rear of the terminal block, where they are separated and soldered to their respective terminal pins. These conductors are shown in solid lines in Fig. 7. In order to simplify the drawing the terminals are not shown in Fig. 7 in their proper relative positions as they are located on the terminal block 80. customary in wiring diagrams and will not cause any confusion. When the device is to be used,

the proper connections to other apparatus and the necessary connections between the relays, keys, etc., which are not a part of the permanent wiring, are made by means of jumpers and by means of strapping on the front side of the terminal block 88. Fig. 7 shows in dotted lines one particular system of strapping which is required for a certain particular use of the multiple pen recordcr.- Other systems of strapping will be described in connection with the description of other uses of the apparatus.

Referring now to Fig. 8, this drawing shows in diagrammatic form the line relay set. This unit comprises a suitable base (not shown) on This departure, however, is.

which the relays and the other apparatus are mounted. Since there is no special novelty in such construction, the details of the base and the way in which the apparatus is mounted thereon is not shown. There are ten line relays, indicated by reference characters 25I to 260, inclusive, each relay being shunted by a condenser. There lS also a slow-acting relay 26!. Each relay has two pairs of contact springs, as shown. On the base there is also mounted a pin terminal block which may be similar to the terminal block which is shown in Fig. 1, except that only four rows of terminals are required.

The terminal block therefore comprises forty terminals, in four rows of ten terminals each. In addition to the foregoing there is provided a key K2l, a flexible cord terminating in a plug P2, and a socket S. All these parts except the plug P2 are suitably mounted on the base along with the terminal block and the relays. The relays, and the contacts thereof are permanently wired up to the terminal block and the wiring is shown in the drawings by solid lines. 7

Fig. 10 is a diagrammatic drawing which shows the so-ealled circuit function counter. This apparatus comprises a suitable base (not shown) on which there is mounted a motor 400, a distributor D, a rotary line switch LS, a number of relays, and four keys K3! to K34. There is also a terminal block comprising 100 pin terminals, which is similar to the terminal block shown in Fig. 1. All this apparatus is suitably mounted as a unit on a convenient form of base or support. Motor 400 is arranged to drive the distributor shaft which carries the'brush arm 450, and the proper intermediate gearing is interposed so that the distributor arm will make six revolutions per minute. The motor and associated gearing may be similar to what is shown in Fig. 1, except for the different gear ratio. The distributor D may be of the known face plate type, and comprises an inner ring 45l, an interrupted ring 452, another ring comprising three sections 453, 454 and 455, and a number of contacts, all as is plainly shown in the drawings. The rotary line switch comprises a stepping magnet 430, an off normal cam 43!, and four wipers 44i-444. The switch is of the type in which the wipers are advanced on the deenergization of the magnet and move in a forward direction only. There are six relays, 40|406. Relays 4M and 402 are two-step relays. The keys K3l-K34 may be of the usual type of telephone key. The

' apparatus is wired up to the pin terminal block as shown. For the sake of clearness, battery and ground symbols are used in this drawing. These symbols indicate connections to the battery and ground conductors 418 and 4'".

The meter set which is shown in Fig. 11 comprises twenty-two meters, which may be similar to the meter which is shown in Fig. 12. Referring to Fig. 12, it may be pointed out that the meter therein depicted comprises an operating coil or magnet, a pivoted armature 522, and a pawl 523 for operating the ratchet wheel 524, which latter is connected to the first digit wheel. There is also a detent 525. The meter has four terminals which project out from the rear end. The two lower terminals 543 and 544, of which only the first can be seen in Fig. 12, are connected to the two ends of the coil winding. The

two upperterminals, 5 and 542, are connected, respectively, to two contact springs 526 and 521.

. These contact springs are closed together by the armature 522 when the same is actuated.

Fig. 11 shows the twenty-two meters assembled in two horizontal rows, in which position they are held by a suitable frame which in turn may be mounted on some appropriate kind of base. This frame and base equipment is not shown as any convenient form thereof can be used. Fig. 11 shows the assembly of meters as seen from the rear, in view of the fact that the drawing is intended primarily to show the connections which are made to the terminals at the back side of the meter assembly. The drawings show in solid lines the various terminal connections that are made between the meter terminals and between the pin terminals on the terminal block. The latter, it should be stated, may be of the same type as those hereinbefore described, except that it need have only two rows of terminals or twenty in all.

Having described the various equipment units, their operation will now be explained. The first unit which will be considered is the multiple pen recorder, shown in Fig. '7. It will be assumed that the apparatus is in use in a telephone system, as for example, an automatic telephone exchange, and an explanation will be given of the operation of the unit in making a record of the calls occurring on a group of ten trunk lines during some selected period. It is generally dosirable to make records of this nature at a time when the approximate peak load is being handled.

In automatic telephone systems a trunk line comprises two talking conductors and a release trunk conductor. Whenever the trunk line is taken for use the release trunk conductor is grounded and this grounded condition is maintained as long as the trunk line continues in use. The trunk lines originate at so-called terminal bays, where they are connected to the cables coming from the banks of the automatic switches through which traffic is directed to the trunk lines, and they terminate at automatic switchboards where they are connected to the jacks of automatic switches. It is convenient, therefore, in using the multiple pen recorder, to set the apparatus up on a table or shelf in the vicinity of the terminal bay, or the automatic switchboard, where ready access can be had to the release trunks of the trunk group which is to be studied. Assuming that this has been done, the

corder'are strapped together as shown by the dotted lines in Fig. '7. This strapping may be done by means of bare wire. The exchange battery should be connected across terminals I89 and I90. This can readily be done by running jumpers from the terminals in question to some point where battery conductors are available, as at the jacks of some switch of the automatic switchboard. Finally the plug PI is inserted in some convenient socket which is connected to the source of'lighting or power supply in the building. As soon as the motor 26 is connected up by plugging in the plug PI, the motor begins to operate, and rotates the driven roller 91 and also the two pick-up spools 85 and 8B. The paper on which the record is to be made should be started on to the pick-up roll [3 provided it is intended to run the apparatus for some time without any attention. However, in the event that only a short study is to be made, say for one hour, or if it is desired to inspect the record at frequent intervals while it is being made, the paper may be fed out from the front of the device, dispensing with the pick-up roller, and may be collected in a basket. It may be desirable to let the paper run out freely in this way even when making an extended study, particularly if portions of the record are wanted as soon as they are made. Lengths of record five or six feet long can readily be cut off with a pair of shears at intervals, so as to prevent too great an accumulation of paper and in order to make use of the record as fast as it is made.

Considering now the operation of the pen mechanism in making the record, it will be seen that each of the pens 1 to 12 will trace a line on the paper as the latter is advanced by the driven roller 91. The type of record that is'produced during the study which is being described now is illustrated in Fig. 1 on that portion of the paper which lies between the dotted lines 690 and Bill. The operation will readily be understood by reference to the circuit which is shown in Fig. 7, and by consideration of the record section referred to. Consider for example the first trunk of the group, the release trunk conductor of which is connected to terminal III. When this trunk line is taken for use, the release trunk becomes grounded, and a circuit is completed which extends from the grounded release trunk conductor of the trunk line by way of terminal III, springs of key KI I, springs of key KI, terminal I 2I strapped to terminal III, winding of relay II, terminal IOI, and thence by way of another strap to the battery terminal I90. The pen relay 'II energizes over the above traced circuit, and closes its contacts 52 and 53. At the same time the #1 pen is moved to the left and the line traced by this pen thereafter until the trunk is released is offset to the left from its normal position. Obviously the length of the offset line is proportional to the duration of the call.

Referring to the fragmentary record which is shown between the dotted lines 690 and BSI of Fig. 1, and particularly to the line traced by the pen #1, the restoration of the offset line at 694 to its normal position indicates the termination of a call, while the resumption of the off-set position of the line at 695 indicates the beginning of a new call. Theline traced by the #3 pen shows a record of a complete call which began and ended during the period of time shown on the record. The beginning ofthe call is indicated by the begining of the oiT-set position of the line at 696-, and the termination of the call isindicated at 69! where the line resumes its normal position. From the foregoing the meaning of the lines traced by all the pens, Nos. 1 to 10, inc usive, will readily be understood.

The #11 pen is used in this study as an overflowpen. In order to explain this it may be pointed out that the various sets of contacts of the pen relays are shown connected together by strapping as to form a chain circuit. The be ginning of this chainis connected to ground by strapping between terminals I89 and I3I. The end of the chain is connected to the eleventh pen relay 8| by strapping between terminals I50 and I82. It will be seen from the foregoing-that when all ten trunks are in use, and all ten of the pen relays are energized, the chain circuit will be completed and pen relay 8I will be energized to move the #11 pen to the left to cause it to trace its line on the paper in off-set position. Referring to Fig. 1, it will be seen that at 698 the #11 pen has traced an oif-set line for a short distance which indicates that during the corresponding period of time all of the trunk lines of the group were busy. I

The record made on the paper shows the relaive lengths of the various calls as they are made, but it may be also necessary to know the actual length of each call. In order to make the record show this, it is only necessary to use ruled paper in which the lines are spaced apart a certain definite distance depending on the speed at which the paper is advanced. However, in making certain tests it is preferably to use unruled paper, and this paper is also somewhat cheaper than the other kind. In order to enable plain paper to be used on all these types of studies where the actual time between the beginning and end of calls has to be indicated on the record, the #12 pen is used to mark the paper as it advances in accordance with the elapsed time. As can be seen from Fig. 7, the spring 34 of the pair controlled by the cam 3| is connected to ground by strapping between terminals I9I and ISO. Spring 33 is connected to the pen relay 82 by strapping between terminals I92 and I86. Therefore, impulses at the rate of ten per minute will be delivered by the springs 33 and 34 to the pen relay 82, controlling the #12 pen. At each impulse the #12 pen will be deflected momentarily to the left, and the marks thus produced on the paper will indicate time periods of six seconds duration. That is, the space between two consecutive marks produced by the pen #12 corresponds in length to a time interval of six seconds. It will be clear now that by comparing therecord of any call with the timing marks on the same length of paper, the duration of such call can readily be ascertained. Further, if the starting time is entered on the chart, the actual time any call is made can be readily figured out.

After making a number of records on a group of ten trunks and finding no overflow periods, the person making the traffic study may desire to arbitrarily reduce the size of the group temporarily in order to ascertain whether or not the trunk group can safely be reduced in size. It may be assumed, for example, that the data obtained so far indicates that possibly a group comprising only eight trunks will satisfactorily handle the traffic. In order to determine whether such is the case or not the keys K9 and KIIl may be operated. The left-hand springs of key KIII disconnect the incoming release trunk conductor circuit from the pen relay and connect it instead to ground, thus marking the tenth trunk line of the group busy. At the same time the right-hand springs of key K10 'close a shunt around the contacts of the pen relay 80. The.

key K9 performs similar functions in respect of the ninth trunk line of the group and the ninth pen relay 19. group of ten trunk lines into a group of only eight trunk lines, by busying artificially the ninth and tenth trunk lines of the group, and at the same time the chain circuit is completed past the ninth and tenth pen relays. Thus, if an overflow condition arises with only eight'trunk lines in service such condition will be indicated on the record by the #11 pen which is the overflow pen. It should be stated in this connection that when the multiple pen recorder is being used These operations convert the trunk line can be cut into service to prevent the loss of calls. 4

It will be clear hat the keys in the row comprising keys KI to KID, inclusive, are useful also in the event that a group of trunks comprising less than ten trunks, is being tested. It is frequently the case that groups of six to nine trunks will be encountered and the apparatus is capable ofbeing readily adapted to such small size trunk groups by operating the proper keys. It may happen also that while testing a group of ten trunks some one trunk will get out of order and have to be removed from service. If this should happen, the key in the row KI-KI 0 which corresponds to the defective trunk is thrown and the test can continue without interruption. A continuous straight line traced on the record by the'pen corresponding to such trunk will indicate that the trunk was out of commission during the test.

If there are some small trunk groups in service of a size which does not exceed five trunks, traffic studies can be made on two of these small trunk groups at the same time. The manner in which the multiple pen recorder is connected up for making traflic studies simultaneously on two small trunk groups will therefore be described briefly, it being assumed that there is one group of five trunks and another group of four trunks on which trafllc data is desired.

In order to connect up the apparatus, the release trunk conductors of the five trunk lines in the first group are connected to terminals ,I'II- I15. The release trunk conductors of the four trunk lines in group #2 are connected to terminals I'll-I80. These connections serve to associate pens 1 to 5 with the five trunks of the first group, respectively, and pens '7 to 10 with the I four trunks of the second group respectively. Pen #11 is preferably used as an overflow pen for the second group, while the #6 pen' may be used as an overflow pen for the first group. The changes in the strapping which are necessary for the proper operation of the overflow pens is as follows: The strap which connects terminals I46 and I31 is removed, and terminal I31 is strapped to ground at some convenient terminal, such as I89, or preferably I51. By grounding terminal I31 in this manner anew chain is prepared through the contacts of the pen relays 11-80, so that when all these relays are energized a circuit will be completed for the #11 pen relay 8|. order to connect up the #6 pen relay 16 as an overflow pen, it is only necessary to strap terminal M6 to terminal I45. The chain circuit through contacts of pen relays II'I5 will operate relay I6 whenever all the relays II-l5 are energized.

From the foregoing explanation it will be readily understood that when the apparatus is put into operation by plugging PI into a source of commercial supply, two trafiic records will be made simultaneously.

An explanation will now be made of the manner in which the apparatus is used for service observing on subscribers lines. Lines which require to be put under observation are usually lines on which the subscribers havebeen making complaints regarding their service. Some times these complaints have no apparent foundation, as the equipment seems to be all right on test, and in order to determine if the complaints are justified, it is desirable to put the lines under observation so that the telephone company can determine just what happens when the complaining subscribers attempt to make calls. It will be clear that a somewhat different type of record is required from the one which has been explained heretofore. It is advisable to obtain, for instance, a record which will show when the receiver was removed, when dialling took place, and

the number actually dialled, the length of the the line relay unit, Fig. 8. It is usually convenient to obtain access to the subscribers lines at the main distributing frame, and accordingly these units may conveniently be set up at some point adjacent to the frame. In .order to connect up a subscribers line for observation, one side of the line is opened at the main frame and is completed through one of the line relays of the line relay unit. The manner in which this is done is shown diagrammatically in Fig. 8, where the first line relay 25I is shown connected up in series with a subscribers line, assumed to be under observation. As is well known, the subscribers lines are connected through the main distributing frame by jumpers, which extend from the cable side of the main frame to the protector or switchboard side. In connecting a Fig. 8 shows that the jumper normally connect- 1 ing terminals 290 and 29I, which are on opposite sides of the main frame, has been disconnected, and a new jumper has been run from terminal 290 to terminal 2| I, and also a new jumper from terminal 20I to 29I. In this manner the relay 25I is connected in series with one side of the subscribers line, so that it can respond whenever a fiow of current is set up over theline. Since there are ten relays 25I-260, all of which may be connected up the same way as relay 25I, the line relay set provides for making service observations on ten lines simultaneously.

The lines which it is desired to observe having been properly connected in to the line relay set, the plug P2 may be inserted in a socket which is connected to the source of commercial current. The exchange battery is connected across the terminals 235 and 236 of the line relay set, and across terminals I89 and I90 of the multiple pen recorder. Plug PI of the multiple pen recorder is inserted in the socket S of observer whenever a call is made on one of the lines under observation. In order to arrange for this alarm circuit the strapping on the terminal block of the multiple pen recorder has to be changed as follows: terminals I3I-I40 should all be strapped together and to ground. Terminal I3I will probably already be connected to ground at terminal I 09, as shown in the drawings. If the other terminals of this row are strapped as shown in the drawings, they can conveniently be multipled together by merely shifting the existing straps. For instance, the strap connecting terminals HI and I32 is removed from terminal MI and connected instead to terminal I3I. Likewise the strap connecting terminal I42 to terminal I33 is removed from terminal I42 and connected to terminal I32, and so on. Terminals I4I-I50 are all strapped together. The eleventh pen relay BI will usually be found connected to terminal I50 as shown in the drawings, and the alarm circuit is therefore connected to terminals I83 and I34. However, it could be connected across terminals I40 and I50. It will be observed that as a result of the foregoing changes in strapping, all of the upper contacts of the pen relays are multipled together, while all of the lower contacts of the pen relays are multipled together and to relay 8|, or to one side of the alarm circuit, if the latter is connected across I50 and I40. Therefore, when any pen relay is operated the alarm circuit will be closed.

Another change that has to be made in the multiple pen recorder in order to adapt the same for service observing is the interchanging of gears 22 and 23 so as to provide for a more rapid advance of the paper. In making this change, gear 2| is removed altogether, and gears 22 and 23 are interchanged, the large gear 22 being placed on the shaft 30, while the small pinion 23 is placed on shaft 98. Since gear 2I has been removed, the take-up spools 85 and 86 are not used, but the paper is merely fed out the front of the machine over the face of roller I3. This is all right, because the apparatus is in operation only when a line under observation is actually making a call and no great quantity of paper is used up. Furthermore, the observer will often want to see what is going on and it would then be objectionable to have the paper rolled up on the take-up spool I3. 1

An extra gear wheel 22 is furnished so that the take-up feature can be used if required. This extra gear is substituted for pinion 23 on shaft 30, while pinion 23 is placed on shaft 98, outside gear 22. The gear case and motor assembly is moved to the left on bracket 25 so that the gear 22 on shaft 30 engages pinion 23 on shaft 98. This leaves the gear 22 shown in Fig. 1 in engagement with gear 2|, which latter does not have to be removed owing to the fact that the added gear 22 is operating in a different plane.

It may be stated here that the necessity for increasing the speed at which the paper is advanced arises from the fact that the dialling impulses have to be recorded. These impulse: are delivered at a rate of approximately ten per second and the paper is therefore required to run at an increased speed so that separate marks will be made on the paper. The shaft 32 revolves once per minute, as mentioned hereinbefore. The ratio between gears 23 and 22 is one to five, and since the driven roll 91 is five inches in circumference,'the paper will be ad-' vanced at a rate of approximately one inch per minute with the gears arranged as shown in the drawings. When the gears are reversed or interchanged, the paper will be speeded up to twenty-five inches per minute. It will be clear that several other speeds could be obtained by providing different sized gears.

The twelfth pen relay 82 may be left connected up as shown in the drawings. It will mark the paper ten times per minute, and since the paper is advancing at the rate of twenty-five inches per minute the space between adjacent marks will be two and one-half inches. Each such space will represent a time interval of six seconds.

Fig. 9 shows the type of record that is made by the multiple pen recorder of a call from a line under observation. Assuming that a call is made from the line which is connected to the first relay 25I of the line relay. set Fig. 8, when the receiver is removed relay 25I will pull up in series with the exchange battery. Upon energizing relay 25I closes its two pairs of contacts and by means of the lower pair completes a circuit for relay 26I. Relay 26I is slow to release, so that it will not respond to subsequent momentary deenergizations of relay 25I. Upon energizing, relay 26I completes a circuit from the commercial power supply to socket S, with the result that current is supplied to the motor 20 of the multiple pen recorder by way of plug PI, so that the advance of the paper is started. Relay 25I also closes a circuit which extends from ground through its upper pair of contacts to terminal HI, and since this terminal is now connected with terminal III of the multiple pen recorder, the circuit continues through the contacts of keys KI I and KI and through the winding of pen relay II to battery. Pen relay 'II accordingly attracts its armature and moves the #1 pen to the left, so that it begins to trace an off-set line. At the same time pen relay II closes its contacts 52 and 53 together, thus completing the alarm circuit to attract the attention of the observer. When the calling subscriber dials the number of the called party the line circuit is interrupted a number of times, and at each interruption relay 25I will fall back and break the circuit of the pen relay II. Thus the interruptions, or dialling impulses, are recorded by means of momentary deflections of the line traced by the pen to the right. When the called subscriber answers the current flow in the line is reversed, and as a result the current flow momentarily falls to zero. This also causes a momentary deenergiz'ation of relay 25I and a momentary restoration of pen relay II, which is duly recorded by the deflection of the line to the right. A- similar occurrence takes place when the called subscriber hangs up his receiver, at which time current in the calling line is reversed back to normal. When the calling subscriber hangs up his receiver, the current flow over the calling line ceases and accordingly relay 25I and the pen relay II are deenergized, Relay 26I also falls back, provided no calls are being made on the other lines which are under observation, and the operation of the multiple pen recorder unit is stopped.

Referring more particularly now to Fig. 9, 210 indicates the point at which the receiver was removed. HI indicates the interval that occu red after the receive" was removed and before dialling began. .tedicates the record ,was 2345. It will also be noticed that a relav tively short interval occurred between the dialling; of the first and second digits. Sometimes trouble is caused by a too fast operation of the dial in dialling the successive digits of the number. 213 indicates theringing period andshows the length of time required for the called subscriber to answer. 214 indicates the point at which answering took place. 215 indicates the period of conversation. 216 indicates the point at which the called subscriber hung up his receiver, while 211 indicates the point at which the calling subscriber hung up his receiver.

It will be seen that the foregoing record shows the observer exactly what took place on the calling line, and he will know what to do in order to' handle the complaint, if any trouble was encountered. If the observer has time toattend to the matter when his attention is directed to the call by the alarm, it is often possible to get in on the calling line and talk to the subscriber at once so that the desired connection can be completed without further delay. However, if it should happen that the observer is occupied at the time, he will nevertheless have a record of what occurred when he inspects the apparatus.

'Referring now to Fig. 11, the operation of the meter set which is there shown will be described. As is the case with the other equipment units, the meter set is mounted on a suitable base so that it can be conveniently moved from point to point in the exchange where ready access can be had to the terminals of the groups of trunk lines on which the traflic data is to be obtained. This meter set is designed to obtain a particular sort of trafflc information relating to a group of ten trunk lines. It will be understood, of course, that any smaller sized group can be handled by cutting out the required numthat since the drawings show the meters as they appear from the rear, the first meter in eachv row appears at the right-hand end of the drawings, and the last meter in each row at the left. Terminal 5I3 is connected to terminal I92 of the multiple pen recorder unit, Fig. '1. If one of these units isavailable and is not being used for any other purpose the unit can be set up adjacent the meter unit, Fig. 11, and the terminals 5I3 and I92 can then be connected together by a short piece of jumper wire. However, if all the multiple pen recording units are in use or if only one is on hand and that one is in use, a temporary wire will have to be run from terminal 5I3 to terminal I92 on such multiple pen recorder, wherever it happens to be located. It will be understood that the multiple pen recorder can be used to make any study which requires it to be run continuously and be available at the same time for use in connection with the meter set. In the event that a multiple pen recorder is available for use with the meter set and is not required at the time for any other purpose, the paper should preferably be removed from the driven roller, so as to avoid unnecessary consumption .of paper. Or the gear 30 can be removed temporarily, so that no power will be transmitted to the driven roll 91. It may be stated that the object of using the multiple pen recorder unit is to obtain a source of timed impulses. Obviously some other source could be used, if available.

When the apparatus is connected up as explained in the foregoing, the first ten meters in the lower row will function as call counters, while the first ten meters in the upper row will function as elapsed time meters. The first meter in each row is, of course, associated with the first trunk line of the group, the second meter in each row with the second trunk line of the group, and so on. The eleventh meter in the upper row functions as an all trunk busy elapsed time meter. The eleventh meter in the lower row is a checking meter. All this will be explained in describing the operation of the meters as calls are set up over the group of trunk lines to which the meter set is connected.

'Assume now that the first trunk line of the group is taken for use. When this occurs, ground is placed on the release trunk conductor of the trunk line, and since this release trunk conductor is connected to the terminal 5M, a circuit will be completed for the #1 meter of the lower row. The meter accordingly operates its armature to register one call. The armature is held attracted throughout the duration of the call and restores when ground is removed from the release trunk conductor at the end of the call.

In its operated position, the armature 522 of the meter closes together a pair of contact springs 526 and 521, these contacts remaining closed throughout the duration of the call. A circuit is thus completed which extends from ground at the multiple pen recorder Fig. 7, by way of the impulse springs 33 and 34, terminal I92, terminal 5I3, contact springs 521 and 526, and the winding of the #1 meter in the upper row to battery. The above circuit is closed by the impulse cam 3I at the rate of ten times per minute, and it follows, therefore, that the #1 meter in the upper row will advance its counting wheels each time an impulse is received. The upper meter, therefore, counts the number of sixsecond periods which are consumed in the call.

The #1 meters operate as described in the foregoing on each call that is set up over the first trunk line of the group. It will be seen that the meters will show the cumulative totals, that is, the #1 meter in the lower row will show the total number. of calls set up since the operation of'the apparatus was started, while the #1 meter in the upper row will show the total elapsed time which was consumed on all of the calls. The other meters 2 to 10, inclusive, of the upper and lower horizontal rows, of course, operate the same in respect to the other trunk lines of the group.

It will be observed that the pairs of contacts on the meters of the upper row are connected together in a chain circuit, which extends from ground at terminal 5 through all of the pairs of contact springs on the upper row of meters in series and thence to the winding of the #11 meter in the upper row. It follows, therefore, that if all of the trunk lines in the group beas minutes meters.

columns provided for each meter.

come busy simultaneously, all the meters 1-10 in the upper row will operate simultaneously, and at each registration will close a circuit for the #11 meter of the upper row, which is the all trunk busy meter. This meter will accordingly register the total elapsed time during which all of the trunk lines of the group were busy. Terminal 5| 3 is connected directly to the winding of the checking meter, which is the eleventh meter in the lower row. This meter, therefore, counts off the total number of impulses that are delivered to the meter unit. The purpose of this record is to enable the observer to make a check by comparing the elapsed time set up on the checking meter with the actual time that the apparatus has been in use as determined from his watch. If the two periods are the same the observer will know that impulses have been received throughout the entire period. This check is useful particularly where the multiple pen recorder from which impulses are being received is located at some other point where it might be stopped for a time by some other person.

In order toobtain the proper data from the meter set, readings must be taken at certain predetermined intervals. For convenience in taking down these readings and making use of them later on, a chart has been devised, a portion of which is illustrated in Fig. 13. This drawing shows a small section cut from the lower lefthand corner of the chart. It will be seen that the chart is ruled off in vertical and horizontal columns. The vertical column at the left is the column in which the time is entered at which the readings are made. Opposite the space for each time entry there are two horizontal columns, one headed by the letter and the other by the letter M. The column C is the one in which the readings of the counting meters are entered, while the M column is the one in which the readings of the elapsed time meters are entered. These latter are sometimes referred to There are two vertical for the first and second meters are partlyshown and it will be understood that the chart is extended to the right far enough to provide similar columns for meters 3 to 11, inclusive. The chart is also extended upward to provide' as many spaces for successive readings as are required, generally twenty-four or more.

In further explanation of the uses of the chart it will be assumed that the apparatus is set up and the meters are read at one oclock. This time is accordingly entered at the bottom of the chart and in the left-hand vertical column. As the meters are read the readings are entered in the proper horizontal columns to the right. As shown by the entries on the chart all the meters read zero when the apparatus was started. Assuming that the meters are read at intervals of an hour, the next reading should be at two pclock, and accordingly this time is entered in the next space in the first vertical column. At two o'clock it can be seen from the each hour is obtained by a process of subtraction. For instance, at four oclock the #1 count- The columns .shown in Fig. 11.

ing meter read 21 and at three o'clock it read 11. Subtracting 11 from 21 gives ten, which is en'- tered in the difference column as shown in the chart. In the same way subtracting from 11, the reading at two oclock from the reading at three oclock, gives 6. Subtracting zero from 5, the initial reading from the reading at two o'clock, gives 5; The chart, therefore, shows that on the first trunk there were five calls during the first hour, six calls during the second hour, and ten calls during the third hour. The elapsed time or total trunk occupation time for each hour is found by a similar process'of subtraction. Since the figures given are for sixsecond intervals, the values obtained can be reduced to minutes by merely pointing off one decimal place, which divides the number by ten. The chart shows that the total time the #1 trunk was occupied during the first hour was 7.5 minutes, during the second hour 9.3 minutes, and during the third hour 14.7 minutes.

If any trunk groups are in use which contain more than ten trunks, two or more meter sets may be connected together and combined into one. For instance, forcollecting traffic data on a group of twenty trunks, two meter sets will be required. Terminals 5H, 5I2, and M3 of the first meter set are connected up as described. The jumper running from terminal 5l4 to the eleventh meter of the upper row of the first set is removed at the latter point and is connected instead to terminal 5 of the second set. In the second set terminal 5 is connected as shown in the drawings. Terminals 5l2 and SH of the second set are connected, respectively, to terminals El! and 516 of the first set.

. The process of collecting certain traffic data through the use of the circuit function counter, Fig. 10, will be explained. This device has the function of automatically and repeatedly testing scribed, the circuit function counter unit, Fig. 10,

is used in connection with the multiple pen recorder unit, Fig. 7, and three of the meter units, Fig. 11. It will be assumed that trafllc data is to be obtained on a group which comprises thirty trunk lines. Accordingly the several units mentioned will be set up together at some convenient point where access can be had to the trunk 11nd terminals.

' After the apparatus has been located, the several units have to be connected together and also connections have to be made to the trunks which are to be tested in order to obtain the required trafllc data. The release trunk conductors of trunks 1 to 30 are connected respectively to terminals Sill-330 of the circuit function counter unit, Fig. 10. The exchange battery is connected to terminals 315 and 314, the grounded side of the battery being connected to terminal 315. Keys Kill, K32 and K33 are left in normal position.

As mentioned above, three meter sets are required, each of which is similar to the one In each set only the lower row of meters is used. Terminals Sill-340 or the circuit function counter unit are connected respectively to terminals 50l-5l0 of the first meter set. Terminals 34l-350 are connected respectively to terminals 50l-5l0 of the second meter setf Terminals 35i-360 are connected respectively to terminals 50l-5l0 of the third meter/set. The ungrounded pole of the exchan e battery is connected to battery terminal 5I2, f each meter set.

Qne multiple pen recorder unit is required. The gears are arranged as shown-in Fig. 2, so that the paper will be advanced at the rate of one inch per minute.

Referring to Fig. 7, the exchange battery is connected to terminal I90. Terminals I6l-l'l0 are connected respectively to terminals 36l-3l0 of the circuit function counter unit, Fig. 10. Terminal'l62, Fig. 7, is disconnected from terminal I50, and terminal I86 is disconnected from terminal I92. Terminals I62 and I66 are then connected respectively to terminals 312 and 3'",

Fig. 10. Keys Ell-K20 are operated.

The apparatus having been connected up as pointed out in the foregoing, plugs Pi and P3 are inserted in sockets which are connected to the commercial power, and the apparatus begins to operate. The operation of the multiple pen recorder unit in advancing the paper and marking the same has already been explained. It may be stated here that the typeof record which is made in the test which is now being described is similar to the one which is shown in Fig. 1 between the dotted hues 692 and 693. As regards the circuit function counter Fig. 10, it will be understood that the motor 400 is connected by means of suitable gearing with the shaft on which the arm 450 of the distributor D1 is mounted so that the arm 450 revolves six times per minute. ,In other words, this arm rotates once every ten seconds. The arm 450 of the distributor has no normal position and therefore it may start from any point. Since this is the case the results of the first test can be disregarded. It will be assumed for the purpose of explanation that the distributor arm has ad=-' vanced from wherever it happened to be to a point where a complete testing operation can begin by testing the first trunk of the group.

On continuing its rotation, the inner brush set on arni 450 closes a connection between rings 45l and 452, thus placing ground on ring 452. At the same time the outer brush set connects contact 456 I with segment 453. The release trunk conductor of the first trunk line of the group is connected to contact 466 by way of terminal 30L If the first trunk line is busy the release trunk conductor will be grounded, and hence there will be a ground on contact 466. Assuming that the first trunk line' is busy, it follows that when contact 466 is connected to to segment 453, a circuit will be completed for relay 404. Belay 404 accordingly operates and at armature 42l closes a circuit for the stepping magnet 430 of the rotary line switch LS. Re-

lay 404 is only operated momentarily as the 85 outer brush set passes over contact 466 and ac-,

cordingly an impulse is delivered to magnet 430.

This causes the switch LS to advance its wipers one step. When the switch takes the first step, the cam 43l on the wiper shaft closes the osnormal contact 432, with the result that a circuit I is closed from ground by way of contact 432,

armature 420, springs of key K33, and winding of relay 406 to battery. Relay '406 therefore {a g agrates and locks itself to the grounded ring I9 to battery at terminal the pen relay 19 will be operated momentarily The distributor continues to operate, and it will be seen that the outer brush set will successively connect the contacts of group 456 to segment 453. After a brief interval the contacts of group 451 are successively connected to segment 454, and after still another interval the contacts of group 458 are succesively connected to segment 455. Segments 454 and 455 are connected to relay 404 the same as segment 453. Accordingly it will be seen that each time the outer brush set of the distributor passes over a contact which isconnected to the release trunk of a busy trunk line, a circuit will be completed for relay 404 and an impulse will be delivered to the stepping magnet 430. Thus the magnet 430 will-receive as many impulses as there are busy trunk lines encountered. It should be stated at this-time that no effect is produced when the outer brush set passes over contacts 460, 463, 46l, and 464, as the conductors which are wired to these contacts are open at springs of key K33. I

. It will be assumed that the first time the group of thirty trunk lines is tested, nine lines are found busy. It follows then that the wipers of the switch 13 will be stepped to the ninth set of contacts. Immediately after testing the last trunk line of the group, the outer brush set of the distributor will place ground on contact 462. As a result a circuit is completed by way of ground and the said contact #62, contacts of key K3I, wiper 444 of switch LS, ninth contact, on which said wiper is resting, terminal 369, terminal I69, Fig. '7, springs of key Ki9, which key is now operated, springs of key K9, and winding of the ninth pen relay l90. As a result of the closure of the above circuit while the brush set is passing contact 462 of the distributor D,

40 and the associated pen will mark the paper. At the same time that the above circuit is completed, another circuit is completed which also includes ground at contact 462 and which extends byway of springs of key K32, armature M6, wiper I of switch LS, ninth contact, on which said wiper is standing, terminal 339, terminal 509 of the first meter set, Fig. 11, and the winding of the operating magnet of the ninth meter to battery at terminal M2. The momentary closure of this circuit results in one operation of the #9 meter in the first set.

As the distributor arm moves along, the inner brush set reaches a point at which the ring 452 discontinues and consequently the ring hecomes ungrounded. Shortly thereafter the outer brush set momentarily connects ground to contact 465. As a result a circuit is completed for relay 403. Relay 403, upon energizing, breaks the circuit of relay 406 at armature 42 6, and since the locking circuit for this relay has already been opened, the relay immediately falls back. Relay 403 also closes a locking circuit for itself at armature 420. At armature 4J9 relay 403 completes a self interrupted circuit for the. stepping magnet 420. The steppi magnet is accordingly operated automatically, and rapidly steps the switch wipers ahead to normal position. when the normal position, is reached, the ofl-normal springs 432 are permitted 70 to open by cam I. This operation stops the further movement of the switch and opens the locking circuit of relay 403, which restores to normal. The stepping magnet 43 6 operates very rapidly in it self interrupted eir- I5 cult and advances the switch at the rate of sixty to seventy stepsper second, so that regardiess of the position in which the wipers are standing when the restoration begins, they will have ample time to be returned to normal before the distributor again reaches the first trunk line of the group.

It will be assumed now that the next time the group of trunk lines is tested fourteen trunks are found busy. Each time a busy trunk line is encountered a circuit is completed for relay 404, and this relay operates the motor magnet 430 to step the switch LS ahead one step, all as has been previously described. When the eleventh busy trunk line is encountered,- the wipers of the switch LS will be stepped to the eleventh contacts in their associated banks. It will be understood that the relay 406 was operated as previously described upon the first step of the switch LS. Now that the switch has been stepped to the eleventh set of contacts in its bank, which is normal position, the of! normal contacts 432 will be opened, but relay 406 remains locked up to the grounded ring 452. Since relay 406 is energized, as soon as the switch is stepped to the eleventh set of contacts, a circuit is completed from ground by way of armature 426 of relay 406, the eleventh bank contact associated with wiper 443, said wiper 445, armature 4| I, and winding of relay 405 to battery. Relay 405 is accordingly energized and at armature 423 completes a circuit for stepping magnet 430 of line switch LS. The magnet therefore operates to advance the'switch automatically one step, so that the wipers arrive at the first set of contacts. This operation opens the circuit of the motor magnet and of relay 405, and the latter, of course, deenergizes. When relay 405 first operates as above described, it completes at armature 422 a circuit for the lower winding of relay 402. Relay 402 is a two-step relay, having its lower winding inefllcient, so that only armature H4 is operated. Theoperation of armature 4I4 closes a locking circuit for relay 402 which includes the upper winding of the relay and ground at the distributor ring 452. The upper winding of the relay 402 is short circuited, however, so long as relay 405 remains operated. As soon as relay 405 falls back, the short'circuit is removed and relay 402 operates completely. Upon completely operating, relay 402 connects ground coming from the distributor ring 452 to terminal 312 by means of armature 4". Since terminal 312 is now connected to terminal I82 of the multiple pen recorder unit, Fig. "I, a circuit is thus completed for the eleventh pen relayll. Pen relay 6| is accordingly operated and the #11 pen begins to trace an off-set line. Relay 402 also transfers the marking conductor coming from contact 462 to the wiper 442 of switch 18. This .erating the multiple pen recorder.

operation is performed at armature 4 I 6.

Since it was assumed that fourteen trunks are busy at the time the. second test is made, three more busy trunk lines will be encountered, re-

for the multiple pen recorder will extend by way of wiper 444 and the fourth contact in its bank, terminal 364, terminal I64, springs of keys K The circuit and K4, and winding of pen relay 14 to battery. This causes the pen associated with the pen relay 14 to make a mark to the left. Since the #11 pen is marking an off-set line now, the mark made by the #4 pen is read as indicating fourteen busy trunks, rather than only four busy trunks. The meter circuit extends by way of the wiper 442 of the line switch LS, now standing on the fourth contact in its bank, by way of terminal 344, terminal 504 of the #2 meter set, and the winding of the fourth meter in that set to battery at terminal M2. The #4 meter of the second set is thus operated. Since the meter operated is the fourth in the second set, it is read as #14, and the fact that this meter has been operated once indicates that when a test was performed fourteen trunks were found to be busy.

After the outer brush of the distributor passes contact 462, the ring 452 becomes ungrounded, and an instant later ground is placed on contact 465. The removal of ground from ring 452 causes relay 402 to become unlocked, so that this relay restores to normal. The grounding of contact 465 closes a circuit for relay 403, and this relay brings about the restoration of the line switch LS as previously described.

It will be assumed now that the next time the group of trunk lines is tested twenty-five trunks are found busy. As explained in the foregoing, each time a busy trunk line is encountered an impulse is delivered to the stepping magnet 430 by means of relay 404, so that when the eleventh busy trunk line is encountered, the wipers of the switch LS will be advanced to the eleventh contact set. The same operations as were pointed out before now take place automatically, the switch wipers being stepped ahead one.step to the first contact set in the bank, and the relay 402 being energized. The eleventh pen relay is energized, relay 8|. Switch LS continues to be stepped ahead as busy trunk lines are encountered, and eventually the wipers will be advanced to the eleventh set of contacts for the second time. As in the previous case, a circuit is completed for relay 405, resulting in the switch wipers being advanced one step to first position. Relay 405 also closes acircuit at armature 422 which now extends by way of armature 4i 5 to relay 40|. Relay 40! is a two-step rel v like relay 402 and only operates its armature 0 when its initial energizing circuit is completed. On

from contact 462 of the distributor to wiper 443 of the switch LS. At armature 4l3 relay 40l completes a circuit which extends from the grounded distributor ring 452 by way'of springs of key K3l, said armature 3, terminal 3', terminal I86, Fig. 7, and the winding of the twelfth pen relay 82 to battery. As a result of the operation of pen relay 82 the #12 pen also begins to mark a line which is off-set to the left.

It was assumed that twenty-five trunk lines are found busy on this test and accordingly the switch LS will take four more steps, its wipers being advanced to the fifth set of contacts. After the last trunk has been tested, the outer brush set will ground contact 462. At this time a circuit will be completed which includes the ground- At armature 4l2 rethe fifth contact in th bank of this wiper, termlnal 365, terminal I65, Fig. '7, springs of keys paper at that point. Since both the #11 and #12 pens are also marking the paper at the same time, the indication is read as 25. That is, the mark made by the pen now means that twenty-five trunk lines were busy.

At the same time that a circuit is completed to the' multiple pen recorder as described in the foregoing, a circuit is completed by way of grounded contact 452, springs of key K32, armature M6, armature H2, wiper 3, fifth contact in the associated bank, terminal 355, terminal 505, Fig. 11, and the winding of the #5 meter of the third set to battery. This meter accordingly is operated. Since the operated meter is in the third set the fact that it has been operated once indicates that at one time when the group of trunks were tested twenty-five of them were found to be busy.

As the distributor arm moves along, ground is disconnected from the ring 452, with the result that relays 5M and 402 are released. Shortly thereafter ground is applied momentarily to contact 465, with the result that relay 403 is energized and the switch LS restored to normal as previously described. It will be understood that the apparatus may continue to operate in the manner described, making a complete test of described is shown between the dotted lines 592 and 693 in Fig. 1. It is thought that this record will be readily understood from the description of the operation of the apparatus which has been given hereinbefore. However, the meaning of the various marks composing the record may be explained briefly. -It will be seen that the first mark was made by pen #8 at 683. This mark indicates that when the trunks were tested iust' prior to the mark being made eight trunks were found busy. The next mark 684 was made by the #4 pen, and in conjunction with the dis-.

placed line drawn by the #11 pen, it indicates that fourteen trunks were found busy. The mark made at I585 indicates that nineteen trunks were found busy. At the time the mark 585 was made bypen #3 we find that pen #12 was operated as well as pen #11, so that the mark 686 a is read asindicating that twenty-three trunks were found busy. For the same reason mark 681 indicates that twenty-one trunks were found busy. The mark at 688 is not accompanied by a second intervals the amount of time which elapsed before any particular mark was made can readily be computed.

Th desired data is obtained from the meter sets by reading them at periodic intervals.

The meters may be read as frequently as is necessary for the information which is desired. For

example, they may be read every hour. The readings are entered on a chart which may be the same as or similar to the chart which is i1- lustrated in Fig. 13, except that the horizontal columns denoted by'the letter M would not need to be used. For entering the readings on a groupof'thirty trunks three charts will be required, or one large chart could be made up. As was explained previously in connection with Fig. 13, the first entries should be made at the bottom of the sheet and successive entries are made in successive horizontal columns. The data for the individual one hour periods, assuming that the meters are read every hour, are-obtained by subtracting the values in each horizontal column from the values in the horizontal column immediately above. If desired, the values for any particular one hour period can be plotted on cross section paper for the purpose of constructing a curve. Such a curve will show the smallest and largest number of trunk lines which are found busy on any test made during the period, and will also show the exact number of times each number of trunks was found to be busy during the period.

Although in the foregoing explanation it has been assumed that both the multiple pen recorder and the meter sets are used to record traffic data simultaneously from the same group of trunks, it should be stated that either of these equipment units can be used separately if desired. For instance, if the key K3l is operated, the multiple pen recorder is cut out and data will be recorded only by means of the meter sets. At certain times of the day the traffic in a telephone exchange is light and records made by the 'multiple pen recorder may not be especially desired. Stopping the pen recorder saves the record paper and also avoids using up the ink. The cost of these items is not of any great importance, but the labor'of installing fresh paper and of filling up the pens is to be avoided so far as possible.

When key K3! is actuated the marking leadwhich comes from contact 452 is disconnected from wiper 444 of switch-1S, and consequently no marking impulses will be transmitted to the pen relays of the multiple pen recorder. The key KSI also disconnects ground at ring 452 from the lower armatures of relays ii and 402, so that when these relays pull up no circuits will be completed for the pen relays 8i and 82. 0bviously also when the multiple pen recorder is cut out by throwing key K, the plug Pl should be removed from the socket so as to stop the motor, unless the recorder is to be used for some other purpose. I

If desired the multiple pen recorder can be used to record alone and the meter sets can be cut out by operating key K32. After the required data is obtained from the meter sets, this data may show that it is desirable to'continue the study for some additional time by means of the multiple pen recorder. When key K32 is operated the marking lead coming from contact 462 is disconnected from armature I" of relay 402, and consequently cannot be con nected. to any of the wipers I, 2 or 3.

The keys KSI and K32 are useful also in that v they afford means for temporarily stopping either the recording of data on the multiple pen recorder or on the meter sets while temporary adjustments or arrangements of the connections are being made.

Trafflc studies of the character which are described in the foregoing can be made on ten trunk groups as well as on groups of larger size. When tests are being made of ten trunk groups,

- trafllc data can be obtained on three groups of sets such as is shown in Fig. '11, and a multiple pen recorder, Fig. 7. The release trunk conductors of the trunk lines of the first group are connected to terminals 30l-3l0 of the circuit function counter unit. The release trunk conductors of the second group are connected to terminals 3ll-320. The release trunk conductors of the third group are connected to terminals 32l-330. The usual battery and ground connections are made, and terminals 312 and 3'" of the circuit function counter unit are connected respectively to terminals I82 and I86 of the multiple pen recorder. As in the preceding case, the terminals 36l-3l0 are connected to terminals Nil-I10. Also the three meter sets are connected up as in the previous case, that is, the first to terminals 33l-340, the second to terminals 34l-350, and the third to terminals 35l-360. Key K33 should be actuated. The apparatus is started in operation by inserting plugs PI and P3 in sockets connected to the commercial current.

Referring now particularly to Fig. 10, when the outer brush of the distributor arm 450 passes contact 466, and assuming that the first trunk line of the first group is busy, an impulse will be transmitted to relay 404. Relay 404 operates and transmits an impulseto the stepping magnet 430 of switch LS, thus advancing the wipers of the switch one step from normal position. Since the circuit of relay 406 is open at key K33, this relay does not operate when the switch moves ofi normal. As successive contacts of the group 456 are passed over by the outer brush set of the distributor, these contacts are tested for ground and each time a ground is encountered an impulse is transmitted to relay 404. Thus the switch LS will be advanced as many steps as there are grounded contacts encountered, or as many times as there are busy trunk lines in the first group. When the outer brush of the distributor passes contact 460 a circuit will be completed which includes contacts of the now actuated key K33 for transmitting marking potential to the first meter set and to the multiple pen recorder, over circuits similar to those described in the previous case. As to the multiple pen recorder, the circuit continues through contacts of key K3l, by way of wiper 444, some terminal of group 36l-310, depending on the number of trunk lines found busy, thence to the multiple pen recorder, Fig. 7, where some pen relay will be momentarily operated. The circuit for the first meter set extends through contacts of key K32 and by way of wiper 44! and some terminal of set 331-340, and thence to the particular meter of the first meter set to which this terminal is connected.

On passing contact brush places ground momentarily on this contact, and closes a circuit which extends through contacts of the operated key K33 to the winding of relay 403. Relay 403 accordingly operates and 453, the outer distributor brings about the release of the switch L8 to nor mal position in a manner which has already been described. Relay 403 also extends ground from the inner ring 452 to the lower winding of twostep relay 402. Relay 402 operates partially as hereinbefore described, and closes a locking circuit for itself at armature 4. When relay 403 falls back, relay 402 operates fully, and at armature4i1 a circuit is completed for the eleventh pen relay 8|. Pen relay 8| accordingly operates, causing the #11 pen to begin to trace an ofi-set line. Relay 402 also shifts the marking conductor to wiper 442 of switch LS. Thus the first group of trunk lines is tested, the results are recorded, and the apparatus is made ready to test the second group of trunk lines.

Since the release trunks of the second group of trunklines are connected to terminals 3- 320, which in turn are connected to contacts 451, the test of thesecond group will begin as soon as the brush set of the distributor reaches the first one of these contacts. Each time a grounded contact is encountered, the switch LS steps ahead one step. When the outer brush of the distributor reaches contact 46l, the marking circuit is completed and a certain pen relay at the multiple pen recorder is momentarily operated and also a particular meter of the #2 meter set will be operated. The particular pen which is actuated and the particular meter which is op.- erated will, of course, depend upon the position to which the switch LS has been advanced. The outer brush of the distributor next passes over contact 464, and closes a circuit for relay 403, which releases the switch 18 to normal. At the same time a circuit is closed again at armature 410, which results in the operation of the twostep relay 40l, similar to the way in which relay 402 was operated. Relay 40| closes a circuit at armature M3 for the twelfth pen relay 82, and at armature 412 connects the marking circuit up to the wiper 443 of the switch LS. v

The distributor arm continues to move along and begins to pass over contacts in group 458, which are associated with the release trunks of the third group of trunk lines. Whenever a grounded contact is encountered the switch LS is stepped ahead as in the previous case, and when contact 462 is passed over the marking circuits are closed to momentarily operate one of the pen relays and also to operate a particular meter in the #3 meter set. When contact 465 is passed over the switch LS is released. Also, just prior to this ground is removed from ring 452 with the result that the locking circuits of relays 40| and 402 are broken and these relays become deenergized.

It will be seen from the foregoing that upon each revolution of the distributor arm each of the three groups of trunk lines will be tested and the result recorded. As regards the data which is recorded on the meter sets, this can be made use of in the same manner as was described inconnection with the previous example, except that it will be understood that three complete sets of readings have to be made, each set relating to a separate group of trunk lines. The readings obtained from the first meter set, which is connected to terminals 33l-340, pertain to the first group of trunk lines, the release trunk conductors of which are connected to terminals 301-3l0. Likewise the readings which are obtained from the second group of meters pertains to the second group of trunk lines, and of course, the readings obtained from the third set of meters pertain to the third group of trunk lines. It will be seen that the three groups of of trunk lines. Since the trunk groups are tested' in the order 1-2--3, if a particular mark refers to the first group of trunk lines, then the next mark will refer to the second and the next to the third, and so on. The group to whichany particular mark refers can be determined by inspection of the markings made by the pens 11 and 12. With both these pens inactive, a

mark made by one of the other pens 1 to 10, inclusive, will refer to the first trunk group. A

mark made by one of the pens 1 to 10, inclusive, while the #11 pen is active, will refer to the second group of trunk lines, while a markmade by one of the pens 1 to 10, inclusive, while the #12 pen is active, will refer to the third group of trunk lines. With this explanation it is thought that the type of record made on the multiple pen recorder will be readily understood and it has-not been thought necessary, there fore, to showa section of such record.

When a comprehensive program for the obtaining of traffic information in a large exchange is started, a somewhat different hook-up will sometimes be found advisable. One such program and the way in which the apparatus is used will be briefly explained by way of example. It will be assumed that there are a large number of ten trunk groups in the exchange and that it is desired to obtain trafiic information on all these trunk groups with a view to making a thorough study of the trunking arrangement to determine if any revisions are necessary;

Two meter sets such as the one shown inFig. 11 are preferably used, the first set being connected to terminals 33l-340 of the circuit function counter, while the second one is connected up to terminals 34I-350. Terminals 35l-360 of the circuit, function counter are connected to terminals l8l-l'l0 of the multiple pen recorder. The latter, however, will not be used at the pre and consequently the motor is not started, and battery is not connected to terminal I90. However, if the battery is connected, the keys Kl l- K20 can be restored. The first two groups of trunk lines to be tested are connected to terminal sets 30l-3l0 and 3i I420, respectively, of the circuit function counter. This unit is now started operating, and may be left operating continuously for the desired period, possibly for twenty-four hours. Readings are taken periodically from the two sets of meters throughout the period of the test. When the test is completed, the trunk lines are disconnected and two more groups will be connected up in place thereof. The same test is now performed in respect to these trunk groups. The operation may continue in this way until all of the trunk groups in the exchange have been gone over and the trafilc data which can be obtained by means of the meter sets has been secured.

Asfast as the traffic data is obtained from the meter sets it is suitably compiled and the results are studied suficient to determine if further data case that the additional information required will be necessary only in respect of some particular hour of the day, and when this time arrives therefore, the multiple pen recorder is placed in operation. The circuit function counter is in use, it will be understood, in performing the routine tests which have been described, and record-- ing the results on the two meter sets. It now begins to test also the group of trunk'lines which is connected to terminals 32l-330 and after each test of such group of trunk lines the result is recorded by way of the wiper 3 of the line switch LS, and the terminals 35I-36li, to which the multiple pen recorder Fig. '7 has been connected. Thus it will be seen that two groups of trunk lines can be tested andthe results can be ,recorded on the meter sets, while at the same timea special test can be run on a third group of trunks and the results can be recorded on the multiple pen recorder.

After a few special tests have been run as described in the foregoing, it may be found that as to some particular group of trunk lines still more detailed information is necessary. Under these circumstances the group of trunk lines in question may be connected up to terminals I'll-I80 of the multiple pen recorder, which is arranged as described hereinbefore for the purpose of making a direct record of the number and duration of all the calls which take place on the group of trunk lines in question. It will be observed that ill-I80 while the multiple pen recorder is in use for recording the information received from the circuit function counter unit. At this time the keys Ki l-K20 will be actuated, so that the terminals Isl-I10, which are connected with the circuit function counter unit.- At this time the way of the keys to the pen relays. As soon as the record which is being made is completed, the keys Ki l-K20 can be restored to normal, thereby connecting terminals Ill-I80 through to the pen relays and disconnecting the latter from terminals IBI-illl. Thus it will be seen that one set of connections can conveniently be prepared while the device is operating to make a record over a different set of connections.

It will be .clear that there are other ways in which the apparatus herein described can be used, and other industrial situations to which they are applicable, aside from automatic telephone systems. It is not possible to describe all the various applications at this time, as such procedure would extend the specification to undue lengths. It will be'sufiicient to say that'the manner in which the equipment is designed, especially the division of the apparatus into a number of separate units of equipment, with the provision of separate sets of terminals on each -equipment unit so as to facilitate changes in the units, interconnection between the units, and the association of the units with operating elements which are to be observed, renders the apparatus exceedingly flexible and capable of being adapted to a great variety of different requirements.

Having described the invention, what is considered to be new and is desired to be protected by Letters Patent will be set forth in the following claims:

What is claimed is:

1. In combination, a multiple pen recorder having a plurality of pens numbered from one to ten, another pen, means for feeding paper along in contact with said pens, means for selectively operating the pens of said plurality to record any digit from one to ten relating to a first group of devices, means for selectively operating the said pens to record any digit from' one to ten relating to a second group of devices, and means foroperating the said other pen also when the second record is made in order to distinguish the group to which the record relates.

2. In a multiple pen recorder, a plurality of pens numbered from one to ten, another pen, means for feeding paper along in contact with said pens, means for selectively operating the pens of said plurality to record digitsfrom one to ten or numbers from eleven to twenty, and means for selectively operating said other pen to enable digits and numbers to be distinguished.

3. Service observing apparatus comprising a relay adapted to be controlled over a subscribers line, a pen recorder including a marking pen, means for continuously feeding paper along in contact with said pen, whereby said pen draws a line on the paper, a magnet for operating said pen to change the position of said line, means controlled by the said relay for starting said feeding means, and a circuit over which said relay controls said magnet.

4. Service observing apparatus comprising, in combination, a multiple pen recorder, a line relay set, means including terminals on the relay set whereby the line relays of said set may be connected in series with lines to be observed, and means including other terminals on the relay set and terminals on the pen recorder whereby any relay of said set can be connected up for operating a particular pen on said pen recorder.

5. The combination, with a plurality of devices subject to changing conditions, of means for testing said devices successively to ascertain if a particular condition exists, a register, means for advancing said register each time one of said plurality of devices is found to be in the condition tested for, recording means controllable in accordance with the position of said register, and means for operating said recording means after the test is completed.

6. The combination, with a plurality of devices subject to changing conditions, of means for testing said devices successively to ascertain if a particular condition exists, a register, means for advancing said register each time one of said plurality of devices is found to be in the condition tested for, a multiple pen recorder having pens and operating magnets therefor connected to the banks of said register, and means effective when the test is completed for closing a circuit for one of said operating magnets through said register.

7. The combination, with a plurality of device subject to changing conditions, of .means for testing said devices successively to ascertain if a particular condition exists, a register, means for advancing said register each time one of said plurality of devices is found to be in the condition tested for, a plurality of meters connected to the banks of said register, and means effective when the test is completed for operating the .connected, testing and registering means controlled over said contacts successively, recording means, a plurality of interspersed marking contacts for controlling the said recording means by way of said registering means, and means for rendering certain of said marking contacts ineffective or effective at will depending on whether the devices to be tested constitute one or a plurality of groups.

9. In combination, a testing device including a register, means for operating said device to perform two series of tests alternately, means for setting the register in accordance with the result of each series of tests, including means for restoring the register after each series of tests is completed, two recording mechanisms of different character, means for transferring the results of all of the first series of tests' from the said register to one recording mechanism, and means for transferring the results of all the second series of tests to the other recording mechanism.

10. In combination, a circuit function counter unit comprising means for testing a group of circuits and including a register which is set in accordance with the result of the test, a multiple pen recorder unit, a meter unit, means including terminals on the said units whereby they may be temporarily connected together to form a tramc testing and recording apparatus, and means whereby the result of a test may be transferred from the said register to either said pen recorder or said meter unit, or to both.

11. In a service observing system, a multiple pen recorder, said recorder including an individual pen for each line to be observed, magnets for operating said pens, respectively, a circuit for each magnet controlled over the associated line, and means responsive to a call on any line for starting said recorder.

12. In a service observing system, a recording pen, means for moving a strip of record receiving material past the pen in contact therewith, means responsive to a call on the line being observed for starting movement of said material, thereby causing said pen to draw a continuous line thereon, means also responsive to such call for deflecting the pen in the plane of said material to change the position of said line, and means responsive to interruptions of the line for momentarily restoring the pen to normal each time an interruption occurs.

13. In a service observing system, a recording pen, means for moving record receiving material past said pen at a predetermined speed and in contact. therewith, whereby said pen draws a continuous line on said material, a magnet for deflecting said'pen in the plane of said material to change theposition of said line, a relay energized over a line under observation when the receiver is removed and deenergized responsive to interruptions of the line and to reversals of current therein, and a circuit for said magnet closed by said relay when the same is energized.

14. In a service observing system, a plurality of recording pens, one for each line being observed, movable recs d receiving material, means responsive to a call on any line for starting movement of said material and for activating the associated pen, and signalling means for indicating to, an attendantthat a record is being made. l t 15. In combination, a plurality of circuits, means for testing said circuits successively, a register, means for setting said register under control of'said testing means, a'recorderf and means for .automatically operating the recorder under control of said register.

16.'In combination, a plurality of circuits,

meansfor testing said circuits successively and for repeating the test periodically, a register, means for setting said register under control of the testing means each time the test is performed, means for restoring the register after each test iscompleted, a recorder, and means for operating the recorder to make a record of the value of each setting of the register before the same is restored.

17. In combination, a multiple pen recorder, a multi-position register, said recorder having as many pens as said register has positions and at least one additional pen, means for variably setting said register in accordance with some numerical value or alternatively in accordance with a greater numerical value less a fixed value, means for operating the recording pen corresponding to the position of the register in any case, and means for operating the said additipnal pen also in the event that said register has its alternative setting.

18. In combination, a multi-position register, a pen recorder including a pen individual to each register position and an extra pen, testing means for setting said register once or twice depending on whether the value determined by the, test does not or does exceed the capacity of the register, means for operating the pen which corresponds to the set position of the register after the test is completed, .and means for operating the extra pen if a double setting of the register has occurred.

19. In combination, a register having a plurality of wipers, testing means for setting said register by transmitting impulses thereto, the

number of impulses being variable between such limits that the register may be advanced through all its positions repeatedly, a control circuit normally associated with one of said wipers, and means for associatingsaid circuit with a dinerent wiper'each time the register leaves its last position.

20. In combination, a register having a plurality of wipers, means for advancing said register through all its positions a plurality of times, counting means responsive each time the register passes aparticular position, a'control circuit, and connections .from'the said circuit to said wipers controlled by said counting means.

' 21. In combination, a register, means for advancing said register through all its positions a plurality of times, counting means responsive each time said register passes a particular position, a pen'recorder, and pen operating circuits selected by said counting means.

22. In combination, a step by step progressively movable switch having a home position, means for transmitting impulses to step said home position and completed through a wiper of the switch in a particular advanced p'osition, counting means, and means controlled over said circuit for operating said counting means, and

also to further step the switch whereby the said circuit is broken.

23. In combination, a distributer, a register,

' means controlled over contacts of the'distributer for advancing the register, recording mechanism,

and circuits for the recording mechanism including the register and another contact of the distributer.

24. In combination, a distributer, a register, means including a series of contacts on said distributer for setting said register, a recording device, an operating circuit tor-said device including the register in set position and another contact of the distributer, and a restoring circuit for the register including another contact of the distributer.

25. In combination, a register, a recording device, circuits for the recording device selectively prepared by said register, a distributor, and means including contacts on the distributer tor first setting the register, then closing the prepared circuit to the recording device, and then restoring the register.

26. In combination, a register having a home position, a distributer, means controlled over contacts of the distributer for stepping said r'egister, a relay energized when the register leaves home position, and a locking circuit for said relay controlled by said distributer.

27. In combination, a register, a distribute means including contacts of the distributer for setting said register, a circuit including the register in set position and another contact of. the distributer, and a second'register controlled over said circuit.

28. In combination, a rotary distributer, a plurality oi registers, a stepby step switch, means for operating the distributer to step the said switch, a circuit for one of said registers prepared by said'switch, and means including a contact of the distributer for closing said circuit.

-29. In a service-observing system, a unit comprising a set of relays each of which is adapted to be connected in circuit with a subscriber's line, a second unit comprising a multiple pen recorder having a pen corresponding to each of said relays, means for connecting said units to enable said relays to control said pens, 'a driving motor and connecting plug included in said second unit, a socket for receiving said plug included in the first unit, and means included in the first unit for connecting a source of power.

to said socket.

30. In a service observing system, a recording pen, a strip of record material in contact with said pen, means for moving-said strip at known speed to cause said pen to draw a record line thereon, a magnet for deflecting said pen to cause the line drawn on said. material to be displaced, a subscribers telephone line, and means responsive to the removal and replacement or the receiver on said telephone line for energizing and deenergizing said magnet, whereby the length of the displaced portion of said record line will constitute a measure of the time the receiver was prising a recording pen, a strip of record ma- I 'terial in contact with sai m switch, a circuit prepared when the switch leaves d pen em f! mov when .the event to be recorded occurs and for retaining it in said new position until the event 

